Whiting

Name:
Whiting
Detailed information:
Finely ground, naturally occurring calcium carbonate, CaCO₃, 98% pure, contaminated with silica, iron, aluminum, or magnesium.

Properties:

White or off-white powder. D 2.7. Insoluble in water; soluble in acids. It has no tinctorial power and hence is not a pigment.

Derivation:

Traditionally from chalk, obtained from England, France, Belgium. A pure limestone or calcite is the principal commercial source. Crude chalk or limestone is ground dry or wet, air- or water-floated, and sieved. Grades are based on particle size, softness, and light reflectance. Dry ground, air-floated limestone whiting can be as fine as 99% through 300-mesh.

Grade:

Various. Paris white is the finest; coarser grades are extra gilders whiting, gilders whiting, and commercial, the last being quite coarse and of poor color. A putty grade is also sold.

Use:

Filler in rubber, plastics, and paper coatings; putty (with linseed oil); whitewashes; sealants.

See Calcium Carbonate; Chalk.